擅长：python、mysql、java
<p>将<code>result</code>和<code>cost</code>设置为索引：</p>
<pre><code>temp = df.set_index(['result', 'cost'])
</code></pre>
<p>从字典生成<code>MultiIndex</code></p>
<pre><code>test_index = pd.MultiIndex.from_tuples(test.items(), names = ['result', 'cost'])
</code></pre>
<p>用<code>temp</code>的索引和<code>test_index</code>的并集重新索引<code>temp</code>：</p>
<pre><code>(temp
.reindex(temp.index.union(test_index, sort = False))
.ffill()
.reset_index()
.reindex(columns = df.columns)
)
date result cost
0 2021-03-01 a 30
1 2021-03-01 d 35
2 2021-03-01 j 98
3 2021-03-01 b 94
4 2021-03-01 a 32
5 2021-03-01 b 21
6 2021-03-01 c 92
</code></pre>
